Cable jacket materials

LSZH materials are typically based on polyolefin plastics. Other common terms for LSZH are LSOH (low smoke zero halogens), LSNH (low smoke no halogens), LSHF (low smoke halogen-free) and FRNC (frame retardant non corrosive). FRNC is often divided into FRNC-B and FRNC-C. The suffixes “B” and “C” denote the test regime specified in the German standard DIN VDE 0472 Part 804. With “B” just one individual cable is tested, with “C” a cable bundle which makes it a more strict regime than “B”.

LSZH materials are more expensive than PVC. They are made for indoor applications and in special versions also for outdoor use, however direct burial is not recommended due to permanent humidity. LSZH materials are less flame retardant than PVC but emit only little and light smoke when burning, which means people should be able to find the emergency exits in case of fire. As LSZH compounds contain no halogens (fluorine, chlorine, bromine, iodine) they do not emit any of these as a corrosive gas when burning. Cable with an LSHZ jacket can be handled nearly as easily as with a PVC jacket, however they are not resistant against water, oil and grease. They can typically be used from -30 °C to + 60 °C. Cables with an LSHZ jacket are typically common in Europe.

Cables with a polyethylene jacket are designed for outdoor applications. PE is UV and weather resistant, water-tight and can withstand high tensile loads. Compared to other jacket materials, PE is rather stiff.Cables with a PE jacket can be used from -55 °C to +60 °C.

Two important variants are LD-PE (low-density polyethylene) with a low mass density (g/cm³) and HD-PE (high-density polyethylene) with a higher one. HD-PE is harder and tougher than LD-PE. PE with medium density (MD-PE) is not common with data cables.

Based on its material and burning characteristics, PE is used for outdoor cables. Cables with a PE jacket are not allowed inside of buildings or only for very short distances, e.g. two meters.

Selecting cables with the proper jacket material is not always easy. The benefits a certain material offers come with drawbacks in other aspects. The European Building Products Regulation added to that problem, as do many national and international standards which have to be followed in many cases. Legitimate and neutral advice which material is the best choice for a certain application is often indispensable.

PVC is a relatively cheap kind of plastic. It is designed for indoor use but not for outdoor use. PVC is more abrasive-resistant and more fire-retardant than LSZH materials. When burning, PVC emits dense, dark smoke as well as toxic chlorine gas which react with water to hydrochloric acid that burns the respiratory system as well as the building stock.

Cables with a PVC jacket can be stripped easily and are contingently resistant against oil and grease. They can typically be used from -40 °C to + 75 °C. Cables with a PVC jacket are common in the US, in Europe cables with an LSZH jacket are preferred.

PUR is resistant against mechanical stress. It withstands high tensile loads and is resistant against wear and tough against hits and indentations. PUR is flexible, can be bent in different directions often without being damaged and stays flexible even at low temperatures. It is resistant against moisture and mineral oils. PUR might contain halogens in very low quantities but is regarded to be practically halogen-free.

Cables with a PUR jacket can typically be used from -40 °C to +85 °C. They are very common in industrial applications, and depending on the polymer compound they can be used in outdoor applications as well.